Liquid crystal display

ABSTRACT

The liquid crystal display device comprises a liquid crystal cell with liquid crystals sealed thereinbetween, sandwiched between two transparent substrates having an electrode on each of the inner surfaces thereof facing each other, an absorption-type polarizing film disposed on the visible side of the liquid crystal cell, a reflection-type polarizing film disposed on the side of the liquid crystal cell, opposite from the visible side. The absorption-type polarizing film is a polarizing sheet absorbing a light linearly polarized in the direction orthogonal to the transmission axis thereof while the reflection-type polarizing film is a polarizing sheet reflecting a light linearly polarized in the direction orthogonal to the transmission axis thereof. A light reflection film or a color filter may preferably be disposed under the reflection-type polarizing film. Further, a light diffusing layer or a light diffusing film may preferably be disposed on the visible side of the absorption-type polarizing film.

TECHNICAL FIELD

The invention relates to a liquid crystal display device for use as adisplay panel in various electronic equipment such as a timepiece (watchand clock), portable information equipment, and so forth.

BACKGROUND TECHNOLOGY

A timepiece for indicating digital display of time information such asthe hour, minute, and second, and calendar information such as the date,days of the week, the month, and the year, by use of a liquid crystaldisplay panel, has been in widespread use for wrist watches and clocks,provided with a crystal oscillation circuit.

There has also been in use a combination watch wherein an analog displayindicating time information by the hands of the watch is used incombination with digital display indicating time information andcalendar information in numbers and letters.

Further, there has been proposed an analog watch for selectivelydisplaying markers in various patterns, or for displaying simulatedhands for an hour hand, a minute hand, and a second hand, by providingthe dial thereof based on a liquid crystal display panel (refer to, forexample, Japanese Patent Laid-open S 54-153066).

A reflective-type liquid crystal display device, small in size andconsuming very little electric power, has been in widespread use as adisplay panel for displaying necessary information (characterinformation and graphic information) in various electronic equipmentother than a timepiece, such as cellular phones, desktop electroniccomputers, game players, and so forth.

As such a liquid crystal display device as described above, in aconventional liquid crystal display panel, a liquid crystal cell filledwith liquid crystals is sandwiched between two transparent substrateshaving an electrode on respective inner surfaces thereof, facing eachother, and an upper polarizing film and a lower polarizing film aredisposed, respectively, on the external surface of the transparentsubstrates, on the opposite sides. If an electric field is applied tothe liquid crystals by applying a voltage to a pair of electrodes on thetransparent substrates holding the liquid crystal cell therebetween, theoptical property of the liquid crystals is changed, thereby locallycontrolling transmission and absorption of light falling on the liquidcrystal display panel such that a predetermined display is effected.

Either of the upper polarizing film or the lower polarizing film is apolarizing film absorbing the light linearly polarized in the directionorthogonal to the transmission axis thereof.

In the case of a watch using the conventional liquid crystal displaypanel described above, time information and calendar information aredisplayed in black against a white background in a normally white modethat is common.

However, by simply displaying time information and calendar informationin black against the white background as described in the foregoing,neither variation in design nor interest can be offered, with aresulting tendency to lose soon popularity with consumers. Probably, asa result, consumption of digital watches has recently been on thedecline, and neither combination watches nor analog watches with aliquid crystal display panel have since received market acceptance.

Similarly, with the conventional liquid crystal display panel used inelectronic equipment other than a timepiece, various informationexpressed in characters and graphics is generally displayed in blackagainst the white background, and although there are some whereininformation can be displayed in white against the black background in aninverse mode, the conventional liquid crystal display panel has stillbeen found lacking in design variation and aesthetic qualities.

In light of the present situation as described, the present inventionhas been developed, and an object of the invention is to provide aliquid crystal display device for use in various electronic equipmentsuch as a timepiece (watch and clock), and so forth, capable of offeringattractive variation in, design and displaying information clearly sothat a viewer can see the display with greater ease.

DISCLOSURE OF THE INVENTION

To this end, a liquid crystal display device according to the inventioncomprises a liquid crystal cell with liquid crystals sealedthereinbetween, sandwiched between two transparent substrates having anelectrode on each of the inner surfaces thereof facing each other, anonly absorption-type polarizing film disposed on a visible side of theliquid crystal cell for a polarizing film, and an only reflection-typepolarizing film disposed on a side of the liquid crystal cell, oppositefrom the visible side thereof for a polarizing film, and ischaracterized in that the absorption-type polarizing film is apolarizing sheet absorbing the light linearly polarized in the directionorthogonal to the transmission axis thereof while the reflection-typepolarizing film is a polarizing sheet reflecting the light linearlypolarized in the direction orthogonal to the transmission axis thereof.

With the liquid crystal display device described above, a lightreflection film is preferably disposed on a side of the reflection-typepolarizing film, opposite from the liquid crystal cell.

Or a color filter may be disposed on a side of the reflection-typepolarizing film, opposite from the liquid crystal cell.

A light reflection film may be further disposed on a side of the colorfilm, opposite from the reflection-type polarizing film.

Furthermore, with the liquid crystal display device described above, alight diffusing layer or light diffusing film is preferably disposed ona visible side of the absorption-type polarizing film.

For the color filter described above, any of an absorption-type colorpolarizing film, a dielectric multi-layered film, or an absorption-typecolor filter is preferably adopted.

Further, it is desirable that, with respect to the liquid crystaldisplay devices described in the foregoing, the absorption-typepolarizing film and the reflection-type polarizing film are disposedsuch that the transmission axes thereof either cross each other at rightangles, or run in parallel with each other.

It is desirable that liquid crystals causing linearly polarized lightpassing therethrough to undergo phase modulation or intensity modulationare sealed in the liquid crystal cell. For such the liquid crystals,twisted nematic liquid crystals, supertwisted nematic liquid crystals,or guest-host liquid crystals are preferably used.

Furthermore, it is desirable that the absorption-type polarizing film isdisposed such that the transmission axis thereof is oriented in thedirection parallel with or orthogonal to the long axes of liquid crystalmolecules located on a visible side of the liquid crystal cell.

With the liquid crystal display device according to the invention,constructed as described above, half of incoming light falling thereonfrom the visible side of the liquid crystal cell is absorbed by theabsorption-type polarizing film but the other half of the incoming lightis transmitted therethrough, falling on the liquid crystal cell, andwhen transmitted through they, liquid crystal cell, transmitted light iscaused to undergo a change in optical property thereof, thereby formingportions of the liquid crystal cell where light is fully reflected bythe reflection-type polarizing film, and other portions thereof wherelight is transmitted therethrough, so that metallic display can beeffected.

Depending on whether the transmission axes of the absorption-typepolarizing film and the reflection-type polarizing film, disposed oneither side of the liquid crystal cell cross each other at right anglesor run in parallel with each other, on whether the transmission axis ofthe absorption-type polarizing film is oriented in the directionparallel with or orthogonal to the direction of the long axes of theliquid crystal molecules located on the visible side of the liquidcrystal cell, or depending on types of liquid crystals in use and themethod of applying a voltage, either of the background part or thedisplay segment of the liquid crystal cell can be displayed in ametallic color through full reflection of incoming light while the othercan be displayed in a dark color, a color of the interior of anelectronic equipment, a color reflected by the light reflection filmdisposed thereunder, or a color transmitted through the color filter.

By way of example, operation is described hereinafter in the casewherein the absorption-type polarizing film and the reflection-typepolarizing film disposed above and below the liquid crystal cell,respectively, are arranged such that the transmission axes thereof runin parallel with each other, and the liquid crystal cell with twistednematic liquid crystals having a twist angle of 90 degrees sealedtherein is used.

Half of the incoming light from the visible side (above) of the liquidcrystal cell is absorbed by the absorption-type polarizing film. Theother half of the incoming light falls on the liquid crystal cell, andis transmitted therethrough. In the background part where no voltage isapplied to the liquid crystals of the liquid crystal cell, transmittedlight is rotated by 90 degrees, and turned into the light linearlypolarized in the direction orthogonal to the transmission axis of thereflection-type polarizing film, thereby being reflected substantiallyin fill by the reflection-type polarizing film. As a result, thebackground part is displayed in a metallic color (as against a mirror).

On the other hand, in the display segment of the liquid crystal cell fordisplaying various information such as time information, calendarinformation, and so forth, where a voltage is applied to the liquidcrystals, light transmitted through the liquid crystal cell is notrotated, and is turned into the light linearly polarized in thedirection parallel with the direction of transmission axis of thereflection-type polarizing film, thereby being allowed to pass throughthe reflection-type polarizing film. Consequently, the display segmentis displayed in a dark color, or can be displayed in a transparent stateso as to show the internal structure of an electronic equipment in whichthe liquid crystal display device is mounted. Otherwise, if the lightreflection film or the color filter is disposed on the underside of thereflection-type polarizing film, the display segment can be displayed inan optional color such as a color reflected by the light reflectionfilm, or a color transmitted through the color filter.

Hence, the invention can provide a liquid crystal display device havingvariation in design and offering users a sense of amusement.

Furthermore, with the liquid crystal display device of the inventiondescribed above, if a light diffusing film or a light diffusing layer isdisposed on the visible side of the absorption-type polarizing film,this will cause light reflected by the reflection-type polarizing filmto be diffused, thereby turning display in a metallic tone into displayin whiter and softer tones so as to be seen by a user with greater easewhile improving a viewing angle characteristic of the liquid crystaldisplay panel as well.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view showing the construction of a firstembodiment of a liquid crystal display device according to theinvention;

FIG. 2 is an enlarged sectional view showing the construction of aliquid crystal cell of the liquid crystal display device;

FIGS. 3 to 9 are schematic sectional views for illustrating theconstruction of second to eighth embodiments of a liquid crystal displaydevice according to the invention, respectively;

FIG. 10 is a perspective view showing the external view of a quartzwatch for illustrating an application example of the liquid crystaldisplay device according to the invention; and

FIG. 11 is a sectional view showing the internal construction of thequartz watch.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of a liquid crystal display device according tothe invention will be described in detail hereinafter with reference tothe attached drawings.

First Embodiment: FIGS. 1 and 2

First, a first embodiment of a liquid crystal display device accordingto the invention, which is the most basic embodiment, is described withreference to FIGS. 1 and 2.

FIG. 1 is a schematic sectional view for illustrating the constructionof a liquid crystal display panel making up the liquid crystal displaydevice, and the Figure shows an enlarged view of a liquid crystal celland respective polarizing films with respect to thicknesses thereof andrespective spacings therebetween.

As shown in FIG. 1, the liquid crystal display panel 10 is made up of aliquid crystal cell 11, absorption-type polarizing film 12 disposed onthe visible side (the upper side in the Figure) of the liquid crystalcell 11, reflection-type polarizing film 14 disposed on the oppositeside (the underside in the figure) of the liquid crystal cell 11.

As shown in FIG. 2, the liquid crystal cell 11 comprises two glasssubstrates 1, 2, and liquid crystals 3 sandwiched between the two glasssubstrates so as to be sealed in with sealing agents 4, and a twistednematic (TN) liquid crystal compound having a twist angle of not morethan 90 degrees is used for the liquid crystals 3.

Transparent electrodes 5, 6, made of indium tin oxide (ITO), are formedon the inner faces of the two glass substrates 1, and 2, respectively,on the side in contact with the liquid crystals 3, and an aligningtreatment is further applied to the inner face of the respectivetransparent electrodes, in contact with the liquid crystals 3, such thatliquid crystal molecules are aligned in a predetermined direction.

The alignment condition of the liquid crystals 3 held between thetransparent electrodes 5, 6 is altered by applying a voltage between thetransparent electrodes 5, 6, thereby indicating various information indigital display or graphic display.

The absorption-type polarizing film 12 and the reflection-typepolarizing film 14, disposed above and below the liquid crystals cell11, respectively, with the liquid crystal cell 11 interposedtherebetween, are arranged so that respective transmission axes arealigned parallel with each other.

Further, the absorption-type polarizing film 12 disposed on the visibleside is installed such that the transmission axis thereof is oriented inthe direction of (that is, in parallel with) the long axes of liquidcrystal molecules located on the visible side of the liquid crystalscell 11.

The absorption-type polarizing film 12 is a polarizing sheet absorbingthe light linearly polarized in the direction orthogonal to thetransmission axis thereof, and is the same as a conventional polarizingfilm in common use.

On the other hand, the reflection-type polarizing film 14 is apolarizing sheet reflecting the light linearly polarized in thedirection orthogonal to the transmission axis thereof. For example, anoptical film, DBEF (trade name), manufactured by Minnesota Mining andManufacturing Co., U.S.A., is used for the reflection-type polarizingfilm 14. The same can be obtained from Sumitomo 3M Co., Ltd., in Japan

The reflective type polarizing sheet described above has been developedby the manufacturer described above, and disclosed in detail in JP (PCT)H9-507308A (International Publication No.: WO95/17691) andJP(PCT)H9-511844A (International Publication No.: WO95/27919).

With the liquid crystal display panel 10 according to this embodiment ofthe invention, half of the external light incoming from above as in FIG.1 is first absorbed by the absorption-type polarizing film 12 disposedthe visible side of the liquid crystal cell 11, and the other halfthereof is transmitted therethrough, falling on the liquid crystal cell11. Since no voltage is applied to the liquid crystals 3 of the liquidcrystal cell 11 in the background part of information display, thetransmitted light falling thereon is rotated through 90 degrees by theliquid crystals 3 (in this case, twisted-nematic crystals) whentransmitted through the liquid crystal cell 11 and is turned to thelight linearly polarizing in the direction orthogonal to thetransmission axis of the reflection-type polarizing film 14.Consequently, the linearly polarized light transmitted through theliquid crystal cell 11 is substantially reflected in fill by thereflection-type polarizing film 14 disposed underneath the liquidcrystal cell 11, and such reflected light outgoes along the optical pathdescribed above but in the reverse direction, thus indicating thebackground part of the information display in a metallic color as isreflected by a mirror.

In the display segment of the liquid crystal cell 11, where a voltagehas been applied for displaying information, incoming light transmittedthrough the absorption-type polarizing film 12 and falling on the liquidcrystal cell 11 is not rotated by the liquid crystals 3 when transmittedthrough the liquid crystal cell 11, and is turned to the light linearlypolarized in the direction running parallel with the direction of thetransmission axis of the reflection-type polarizing film 14, therebybeing allowed to pass through the reflection-type polarizing film 14.

Accordingly, if a light absorption member (layer, film, sheet, etc.) isinstalled on the underside of the liquid crystal display panel 10, mostof the light transmitted through the reflection-type polarizing film 14will be absorbed thereby, so that light reflected towards the visibleside will be eliminate thus indicating the display segment in a black ora dark color.

However, if a white film, a gray film, or a variously colored film (orsheet) is installed in place of the light absorption member, irregularreflection therefrom causes information to be displayed colorfully in awhite, a gray, or an optional color, distinct from a metallic color inwhich the background is displayed.

Otherwise, by mounting the liquid crystal display panel 10 as it is inan electronic equipment such as an electronic timepiece, and so forth,it is possible to display the background part in the metallic colorwhile, in the display segment for displaying information, the internalstructure of the electronic equipment will become visible from theoutside, thereby providing an amusing display.

Accordingly, in marked contrast with the conventional liquid crystaldisplay panel for indicating digital display of time information,calendar information, and so forth, and indicating display of variousinformation in a black or a dark color against the background in a whiteor a gray color, the liquid crystal display panel according to theinvention is capable of indicting display in a transparent color or inan optional color against the background, in a metallic tone, offeringvariation and enhancing a user's sense of amusement.

Further, if the absorption-type polarizing film 12 and thereflection-type polarizing film 14, disposed above and below the liquidcrystal cell 11, respectively, with the liquid crystal cell 11interposed therebetween, are arranged such that respective transmissionaxes thereof cross each other at right angles so as to conform to thetwist angle of the liquid crystals 3, the display condition can beinverted between the background part and the display segment, therebyenabling various information to be displayed in a mirror-like metalliccolor against the background in a dark, a transparent or an optionalcolor.

Needless to say, it is to be pointed out that the invention is appliedto not only a liquid crystal display device using a liquid crystaldisplay panel for indicating digital display wherein the electrodes 5, 6of the liquid crystal cell 11 are formed in a plurality of segmentpatterns such as a seven-segment pattern for displaying numbers, and soforth, but also to a liquid crystal display device using a liquidcrystal display panel for displaying various characters and graphicswherein the electrodes 5, 6 of the liquid crystal cell 11 are formed ina dot-matrix pattern.

The case wherein the liquid crystals that are sealed in the liquidcrystal cell 11 are twisted nematic (TN) liquid crystals, causinglinearly polarized light passing therethrough to undergo phasemodulation, has been described in the foregoing by way of example.However, supertwisted nematic (STN) liquid crystals and guest hostliquid crystals causing linearly polarized light passing therethrough toundergo intensity modulation may be used instead.

The guest-host liquid crystals belong to a mixed type liquid crystal andare produced by dissolving a dichroic dye as solute in liquid crystalcompounds as solvent. If the alignment condition of the guest-hostliquid crystal molecules is caused to change by applying an electricfield thereto, alignment of the dichroic dye can be controlled followingmovement of the guest-host liquid crystal molecules, thereby indicatingdisplay after modulating absorption of light incoming from a givendirection.

Accordingly, by putting the guest host liquid crystals to use as theliquid crystals 3 of the liquid crystal cell 11 in the liquid crystaldisplay panel described above, it is made easier to color the displaysegment against the background shown in a metallic color.

Second to Eighth Embodiments: FIGS. 3 to 9

Now, second to eighth embodiments of a liquid crystal display deviceaccording to the invention are described with reference to FIGS. 3 to 9.FIGS. 3 to 9 are schematic sectional views, similar to FIG. 1, eachshowing the construction of a liquid crystal display panel used incarrying out the respective embodiments of a liquid crystal displaydevice according to the invention. In these figures, parts correspondingto those previously described with reference to FIG. 1 are denoted bythe same reference numerals, and description thereof is omitted.

FIG. 3 shows the construction of a liquid crystal display panel used inthe liquid crystal display device according to the second embodiment ofthe invention, and this liquid crystal display panel differs from theliquid crystal display panel according to the first embodiment of theinvention, as shown in FIG. 1, only in that a light reflection film 15is disposed on a side (the underside in the figure) of a reflection-typepolarizing film 14, opposite from a liquid crystal cell 11, thereflection-type polarizing film 14 being disposed on a side of theliquid crystal cell 11, opposite from a visible side thereof.

For the light reflection film 15, a member made of a film-like substratewith a film of metal such as aluminum, nickel and so forth, formedthereon, or a dielectric multi-layered film is used. Further, a lightreflection film with a mirror-like surface may be used, however, a lightreflection film in a gold color with somewhat roughened surface, a lightreflection film in a white or a gray color, or a colored lightreflection film causing a light component at a specific wavelength onlyto undergo irregular reflection (any of these light reflection films maybe a light reflection sheet or a light reflection film provided withcoating etc.) may be used as well.

Light transmitted through the reflection-type polarizing film 14 can bereflected by the light reflection film 15 so as to outgo towards thevisible side along the same optical path as that for incoming light butin the reverse direction.

As a result, a utilization efficiency of light is enhanced, enablingbright display to be executed by virtue of a metallic color in sharpcontrast with a white color, a gray color, or an optional color.

Further, in the case wherein the light reflection film with themirror-like reflection surface is used for the light reflection film 15,both the background part and the display segments will be in a displaycondition in a metallic tone due to total reflection. However, colortones of respective parts can be differentiated as those of silveragainst gold, and in addition, display, when seen from a somewhat slantviewing angle, will have a three-dimensional effect due to a differencein the position of light reflection between the respective parts.

FIG. 4 shows the construction of a liquid crystal display panel used inthe liquid crystal display device according to the third embodiment ofthe invention. This liquid crystal display panel differs from the liquidcrystal display panel according to the first embodiment of theinvention, as shown in FIG. 1, only in that a color filter 16 isdisposed on a side (the underside in the figure) of a reflection-typepolarizing film 14, opposite from a liquid crystal cell 11, thereflection-type polarizing film 14 being disposed on a side of a liquidcrystal cell 11, opposite from a visible side thereof.

For the color filter 16, an absorption-type color polarizing film, adielectric multi-layered film, or a selective absorption-type filter isadopted.

As a component of light transmitted through the reflection-typepolarizing film 14, at a specific wavelength only, can be transmittedthrough the color filter 16 which is disposed underside of thereflection-type polarizing film 14, display parts for variousinformation can be colored by disposing a white film thereunder.

FIG. 5 shows the construction of a liquid crystal display panel used inthe liquid crystal display device according to the fourth embodiment ofthe invention. This liquid crystal display panel differs from thecrystal display panel according to the first embodiment of theinvention, as shown in FIG. 1, only in that a light diffusing film(scattering film) 17 is disposed on a visible side (the topside in theFigure) of an absorption-type polarizing film 12 disposed on a visibleside of a liquid crystal cell 11.

The light diffusing film 17 is formed, for example, by applying a binderwith silica particles consisting of silicon oxide, acrylic beads, orcalcium powders that are mixed therein to a transparent film-likesubstrate. Or the light diffusing film 17 may be formed by applyingembossing to the surface of a transparent base film The light diffusingfilm 17 may be formed by sticking such a film described above directlyto the upper surface of the absorption-type polarizing film 12, or bycoating the same with a light diffusion agent.

With such a construction as described above, wherein the light diffusingfilm 17 or a light diffusing layer is disposed on the visible side ofthe absorption-type polarizing film 12, light reflected by thereflection-type polarizing film 14 acting like a mirror is diffused,thereby moderating a metallic tone in which the background part isindicated and turning the display into softer and more elegant toneswhile improving a viewing angle characteristic of the liquid crystaldisplay panel as well.

FIG. 6 shows the construction of a liquid crystal display panel used inthe liquid crystal display device according to the fifth embodiment ofthe invention. This liquid crystal display panel differs from thecrystal display panel according to the fourth embodiment of theinvention, as shown in FIG. 5, only in that a color filter 16 isdisposed on a side (the underside in the figure) of a reflection-typepolarizing film 14, opposite from a liquid crystal cell 11.

The color filter 16 is of the same kind as the color filter 16 describedin the third embodiment of the invention with reference to FIG. 4.

Accordingly, the liquid crystal display panel according to the fifthembodiment has the function of the liquid crystal display panelaccording to the third embodiment (FIG. 4) in combination with that ofthe fourth embodiment (FIG. 5), so that display can be indicated insofter and more elegant tones by moderating a metallic tone in which thebackground part is indicated while improving a viewing anglecharacteristic and capable of displaying information in an optionalcolor.

FIG. 7 shows the construction of a liquid crystal display panel used inthe liquid crystal display device according to the sixth element of theinvention. This liquid crystal display panel differs from the crystaldisplay panel according to the fourth embodiment of the invention, asshown in FIG. 5, only in that a light reflection film 15 is disposed ona side (the underside in the Figure) of a reflection-type polarizingfilm 14, opposite from a liquid crystal cell 11.

The light reflection film 15 is of the same kind as the light reflectionfilm 15 described in the second embodiment of the invention withreference to FIG. 3.

Accordingly, the liquid crystal display panel according to the sixthembodiment has the function of the second embodiment (FIG. 3) incombination with that of the fourth embodiment (FIG. 5), so that displaycan be indicated in softer and more elegant tones by moderating ametallic tone in which the background part is indicated while improvinga viewing angle characteristic and capable of providing a bright displayby improving the utilization efficiency of light.

FIG. 8 shows the construction of a liquid crystal display panel used inthe liquid crystal display device according to the seventh embodiment ofthe invention. This liquid crystal display panel differs from thecrystal display panel according to the third embodiment of theinvention, as shown in FIG. 4, only in that a light reflection film 15is disposed on a side (the underside in the figure) of a color filter16, opposite from a reflection-type polarizing film 14.

This light reflection film 15 is of the same kind as the lightreflection film 15 described in the second embodiment of the inventionwith reference to FIG. 3.

Accordingly, the liquid crystal display panel according to the seventhembodiment has the function of the third embodiment (FIG. 4) incombination with that of the second embodiment (FIG. 3), so that lighttransmitted through both the reflection-type polarizing film 14 and thecolor filter 16 is reflected by the light reflection film 15 towards thevisible side. As a result, colored display of various information can beprovided against the background in a metallic tone while the display canbe rendered brighter by improving the utilization efficiency of light.

FIG. 9 shows the construction of a liquid crystal display panel used inthe liquid crystal display device according to the eighth embodiment ofthe invention. This liquid crystal display panel differs from thecrystal display panel according to the seventh embodiment of theinvention, as shown in FIG. 8, only in that a light diffusing film 17 isdisposed on a visible side (the topside in the figure) of theabsorption-type polarizing film 12.

The light diffusing film 17 is of the same kind as the light diffusingfilm 17 described in the fourth embodiment of the invention withreference to FIG. 5, and may be a light diffusing layer.

Accordingly, the liquid crystal display panel according to the eighthembodiment has the function of the seventh embodiment of the inventionas described with reference to FIG. 8 in combination with that of thefourth embodiment of the invention as described with reference to FIG.5, so that a bright display can be indicated in softer and more eleganttones by moderating a metallic tone in which the background part isindicated while improving a viewing angle characteristic of the liquidcrystal display panel.

In any of the embodiments described in the foregoing, variousmodifications described in the first embodiment can be applied for thesame effects.

Application Example of the Liquid Crystal Display Device of theInvention

Now a digital quartz watch wherein the liquid crystal display deviceaccording to the invention is used will be described hereinafter by wayof example.

FIG. 10 is a perspective view of the watch showing the external viewthereof and FIG. 11 is a sectional view showing the internal structurethereof.

A case 20 of the quartz watch comprises of a glass 22 and a case back23, integrally joined with a case body 21 made of metal.

The glass 22 is made of a transparent material such as sapphire glass,tempered glass, or plastic, and is integrally joined with the front faceof the case body 21 by means of direct bonding, or fitting therein usingpacking. The case back 23 is integrally joined with the back face of thecase body 21 by means of screws or fittings using packing.

Thus, the case 20 has an airtight inner structure so as not to allowingress of dust or moisture.

A liquid crystal display panel (liquid crystal display device) 10 toserve as a display for indicating time and so forth is installed on theside of the glass 22 inside the case 20.

The liquid crystal display panel 10 comprises a time display section 10a for displaying the hour, minute, and second, a calendar displaysection 10 b for displaying month, day, days of the week, and a colonmark display section 10 c that blinks every second, for example.

Further, the liquid crystal display panel 10 is capable of displayingfunctions including time display for 12 consecutive hours or 24consecutive hours as usual, an alarm function, a stopwatch function, atimer function, and so forth.

Changeover among such various functions, and correction of time, areexecuted by manipulating a plurality of switching buttons 24 installedin the side of the case body 21 of the case 20. A packing is providedbetween each of the switching buttons 24 and the case body 21 so as notto allow ingress of dust and moisture into the case 20.

As shown in FIG. 11, the quart watch has an inner structure such thatthe liquid crystal display panel 10 and a printed circuit board 30 aredisposed substantially parallel with each other inside the case 20, anda battery 31 for serving as a driving power source of the printedcircuit board 30 is installed on the case back 23 side of the printedcircuit board 30.

A semiconductor integrated circuit 33 comprising a crystal oscillator 32having an oscillation frequency of 32,768 Hz, a crystal oscillationcircuit for generating a predetermined signal by oscillating the crystaloscillator, a counting-down circuit, a driving circuit for driving theliquid crystal display panel 10, a central processing unit (CPU) foroverall control of the quartz watch, and so forth, is mounted on theprinted circuit board 30.

The liquid crystal display panel 10 is electrically connected with theprinted circuit board 30 via a zebra-rubber connector 34 disposedtherebetween. The zebra-rubber connector 34 is disposed so as to becompressed thicknesswise in order to ensure electrical connectionbetween the liquid crystal display panel 10 and the printed circuitboard 30.

The zebra-rubber connector 34 is made up of electrically conductivelayers, composed of insulating silicone rubber with carbon and metallicparticles contained therein, and formed at a predetermined pitch, andelectrically conductive in the direction of thickness thereof via therespective electrically conductive layers, but is in a transverselyinsulated condition between adjacent electrically conductive layers.

A connection terminal pattern is formed on the faces of the liquidcrystal display panel 10 and the printed circuit board 30, opposite toeach other, respectively, in such a fashion as to correspond tovertically conductive parts of the zebra-rubber connector 34, formed ofthe electrically conductive layer, respectively, and insulation parts ofthe zebra-rubber connector 34, alternately disposed, and in dimensionsat the same pitch as that for the vertically conductive parts.

With the watch, external light falling on the reflective-type liquidcrystal display panel 10 from the side of the glass 22 (the visibleside) can indicate digital display of time information such as the hour,minute, and second, and calendar information such as date, days of theweek, month, and year in various states (in a dark color, a white color,various other colors, or in such a state as to allow the internalstructure of the watch to be visible from outside) against thebackground shown in a metallic tone.

Conversely, the display condition can be inverted between the backgroundpart and the display segment of the liquid crystal display panel 10 sothat time information, calendar information, and so forth can bedisplayed in a metallic tone.

Any of the liquid crystal display panels described hereinbefore in thefirst to the eighth embodiments may be used as the liquid crystaldisplay panel 10.

With the liquid crystal display panel 10, an internal light source isnot required because display is indicated through reflection of incomingexternal light However, in order to enable display to be executed evenin locations where no external light is available, for example, at nightor dark locations, a backlight may be installed on the underside of theliquid crystal display panel 10 (shown in any of FIGS. 1, 4, 5 and 6),so that transmission display can be effected by lighting up thebacklight only when any of the switches 24 is pressed down.

INDUSTRIAL APPLICABILITY

As described in the foregoing, with the liquid crystal display deviceaccording to the invention, various information can be displayed invarious states such as in a dark color, a white color, various othercolors, or in such a state as to allow the internal structure of anelectronic equipment to be visible from outside against the backgroundlike a mirror or in a softened metallic tone when external light fallsthereon.

Further, by inverting display conditions between the background part andthe information display segment of the liquid crystal display panel,characters, numbers, graphics, or so forth for representing variousinformation can be displayed in a metallic tone.

Accordingly, the liquid crystal display device according to theinvention can be used as a display panel incorporated in variouselectronic equipment such as a digital quart timepiece, other portableelectronic equipment and so forth, thereby enabling novel and amusingelectronic equipment adaptable to variation in design to be provided.

What is claimed is:
 1. A liquid crystal display device comprising: aliquid crystal cell with liquid crystals sealed therein between,sandwiched between two transparent substrates having an electrode oneach of inner surfaces thereof facing each other; an onlyabsorption-type polarizing film disposed on a visible side of the liquidcrystal cell for a polarizing film; and an only reflection-typepolarizing film disposed on a side of the liquid crystal cell, oppositefrom the visible side thereof for a polarizing film; saidabsorption-type polarizing film is a polarizing sheet absorbing lightlinearly polarized in the direction orthogonal to the transmission axisthereof; said reflection-type polarizing film is a polarizing sheetreflecting light linearly polarized in the direction orthogonal to thetransmission axis thereof, wherein a color filter is disposed on a sideof the reflection-type polarizing film, opposite from the liquid crystalcell.
 2. A liquid crystal display device according to claim 1, whereinthe color filter is an absorption-type color polarizing film, adielectric multi-layered film, or an absorption-type color filter.
 3. Aliquid crystal display device according to claim 1, wherein a lightdiffusing layer, or a light diffusing film is disposed on a visible sideof the absorption-type polarizing film.
 4. A liquid crystal displaydevice according to claim 1, wherein a light reflection film is disposedon a side of the color filter, opposite from the reflection-typepolarizing film.
 5. A liquid crystal display device according to claim1, wherein the absorption-type polarizing film and the reflection-typepolarizing film are disposed such that the transmission axes thereofcross each other at right angles.
 6. A liquid crystal display deviceaccording to claim 1, wherein the absorption-type polarizing film andthe reflection-type polarizing film are disposed such that thetransmission axes thereof run in parallel with each other.
 7. A liquidcrystal display device according to claim 1, wherein the liquid crystalcell with twisted nematic liquid crystals sealed therein between,sandwiched between two transparent substrates having an electrode oneach of inner surfaces thereof facing each other.
 8. A liquid crystaldisplay device according to claim 1, wherein the liquid crystal cellwith supertwisted nematic liquid crystals sealed therein between,sandwiched between two transparent substrates having an electrode oneach of inner surfaces thereof facing each other.
 9. A liquid crystaldisplay device according to claim 1, wherein the liquid crystal cellwith guest-host liquid crystals sealed therein between, sandwichedbetween two transparent substrates having an electrode on each of innersurfaces thereof facing each other.
 10. A liquid crystal display deviceaccording to claim 1, wherein the absorption-type polarizing film isdisposed such that the transmission axis thereof is oriented in thedirection parallel with or orthogonal to the long axes of liquid crystalmolecules located on a visible side of the liquid crystal cell.
 11. Aliquid crystal display device according to claim 4, wherein the lightreflection film is a member made of a film-like substrate with a film ofmetal, or a dielectric multi-layered film.
 12. A liquid crystal displaydevice according to claim 4, wherein the light reflection film is onewith a mirror-like surface or a roughened surface, or a colored lightreflection film causing a light component at a specific wavelength onlyto undergo irregular reflection.